Zúñiga M, Champomier-Verges M, Zagorec M, Pérez-Martínez G
Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (CSIC), 46100 Burjassot, Valencia, Spain.
J Bacteriol. 1998 Aug;180(16):4154-9. doi: 10.1128/JB.180.16.4154-4159.1998.
Lactobacillus sake can use arginine via the arginine deiminase (ADI) pathway. We designed degenerate primers based on an alignment of known sequences of ornithine transcarbamoylase (OTC)-encoding genes in order to amplify the L. sake counterpart sequences by PCR. Screening a genomic library of L. sake in lambdaEMBL3 allowed us to isolate a clone containing a 10-kb L. sake genomic DNA insert. Sequence analysis revealed that the genes involved in arginine catabolism were clustered and encoded ADI (arcA), OTC (arcB), carbamate kinase (arcC), and a putative carrier with high similarity to the arginine/ornithine antiporter of Pseudomonas aeruginosa (arcD). Additionally, a putative transaminase-encoding gene (arcT) was located in this region. The genes followed the order arcA arcB arcC arcT arcD, which differs from that found in other microorganisms. arcA, arcB, arcC, and arcD mutants were constructed, and the ADI pathway was impaired in all of them. Transcriptional studies indicated that arcA gene is subject to catabolite repression, and under the conditions used, several transcripts could be detected, suggesting the existence of different initiation sites or processing of a larger mRNA.
清酒乳杆菌可通过精氨酸脱亚氨酶（ADI）途径利用精氨酸。我们基于鸟氨酸转氨甲酰酶（OTC）编码基因已知序列的比对设计了简并引物，以便通过聚合酶链反应（PCR）扩增清酒乳杆菌的对应序列。筛选λEMBL3中的清酒乳杆菌基因组文库使我们能够分离出一个含有10 kb清酒乳杆菌基因组DNA插入片段的克隆。序列分析表明，参与精氨酸分解代谢的基因成簇排列，编码ADI（arcA）、OTC（arcB）、氨基甲酸激酶（arcC）以及一个与铜绿假单胞菌精氨酸/鸟氨酸反向转运体高度相似的推定载体（arcD）。此外，一个推定的转氨酶编码基因（arcT）位于该区域。这些基因的排列顺序为arcA arcB arcC arcT arcD，这与在其他微生物中发现的顺序不同。构建了arcA、arcB、arcC和arcD突变体，并且它们的ADI途径均受损。转录研究表明，arcA基因受到分解代谢物阻遏，在所使用的条件下，可以检测到几种转录本，这表明存在不同的起始位点或较大mRNA的加工过程。
